WASHINGTON (Reuters) - The Federal Aviation Administration (FAA) said on Wednesday it would order inspection of some 220 jet engines after investigators said a broken fan blade touched off the explosion on a Southwest Airlines flight, shattering a window and killing a passenger.

The so-called air-worthiness directive would require an ultrasonic inspection within the next six months of the fan blades on all CFM56-7B engines that have accrued a certain number of flights.

Reporting by David Shepardson; Writing by Dan Whitcomb; Editing by Sandra Maler